mcs/class/System.XML/System.Xml/XmlInputStream.cs

   1 //
   2 // System.Xml.XmlInputStream
   3 //      encoding-specification-wise XML input stream and reader
   4 //
   5 // Author:
   6 //      Atsushi Enomoto (ginga@kit.hi-ho.ne.jp)
   7 //
   8 //      (C)2003 Atsushi Enomoto
   9 //
  10 using System;\r
  11 using System.IO;\r
  12 using System.Text;\r
  13 using System.Xml;\r
  14 \r
  15 namespace Mono.Xml.Native\r
  16 {\r
  17         #region XmlStreamReader
  18         public class XmlStreamReader : StreamReader
  19         {
  20                 XmlStreamReader (XmlInputStream input)
  21                         : base (input, input.ActualEncoding != null ? input.ActualEncoding : Encoding.UTF8)
  22                 {
  23                 }
  24
  25                 public XmlStreamReader (Stream input)
  26                         : this (new XmlInputStream (input))
  27                 {
  28                 }
  29
  30                 public XmlStreamReader (string url)
  31                         : this (new XmlInputStream (url))
  32                 {
  33                 }
  34         }
  35         #endregion
  36 \r
  37         class XmlInputStream : Stream\r
  38         {\r
  39                 Encoding enc;\r
  40                 Stream stream;\r
  41                 byte[] buffer = new byte[256];\r
  42                 int bufLength;\r
  43                 int bufPos;\r
  44 \r
  45                 static XmlException encodingException = new XmlException ("invalid encoding specification.");\r
  46 \r
  47                 public XmlInputStream (string url)\r
  48                 {\r
  49 #if NetworkEnabled\r
  50                         try {\r
  51                                 Uri uri = new Uri (url);\r
  52                                 Initialize (new MemoryStream (new System.Net.WebClient ().DownloadData (url)));\r
  53                         } catch (UriFormatException ex) {\r
  54                                 Initialize (new FileStream (url, FileMode.Open));\r
  55                         }\r
  56 #else\r
  57                         Initialize (new FileStream (url, FileMode.Open, FileAccess.Read));\r
  58 #endif\r
  59                 }\r
  60 \r
  61                 public XmlInputStream (Stream stream)\r
  62                 {\r
  63                         Initialize (stream);\r
  64                 }\r
  65 \r
  66                 private void Initialize (Stream stream)\r
  67                 {\r
  68                         // FIXME: seems too waste...\r
  69                         MemoryStream ms = new MemoryStream ();\r
  70                         this.stream = stream;\r
  71                         int c = stream.ReadByte ();\r
  72                         switch (c) {\r
  73                         case 0xFF:\r
  74                                 c = stream.ReadByte ();\r
  75                                 if (c == 0xFE) {\r
  76                                         // BOM-ed little endian utf-16\r
  77                                         enc = Encoding.Unicode;\r
  78                                 } else {\r
  79                                         // It doesn't start from "<?xml" then its encoding is utf-8\r
  80                                         enc = Encoding.UTF8;\r
  81                                         ms.WriteByte ((byte)0xFF);\r
  82                                         ms.WriteByte ((byte)c);\r
  83                                 }\r
  84                                 break;\r
  85                         case 0xFE:\r
  86                                 c = stream.ReadByte ();\r
  87                                 if (c == 0xFF) {\r
  88                                         // BOM-ed big endian utf-16\r
  89                                         enc = Encoding.BigEndianUnicode;\r
  90                                         return;\r
  91                                 } else {\r
  92                                         // It doesn't start from "<?xml" then its encoding is utf-8\r
  93                                         enc = Encoding.UTF8;\r
  94                                         ms.WriteByte ((byte)0xFE);\r
  95                                         ms.WriteByte ((byte)c);\r
  96                                 }\r
  97                                 break;\r
  98                         case 0xEF:\r
  99                                 enc = Encoding.UTF8;\r
 100                                 c = ReadByte ();\r
 101                                 if (c == 0xBB) {\r
 102                                         c = ReadByte ();\r
 103                                         if (c != 0xBF) {\r
 104                                                 ms.WriteByte ((byte)0xEF);\r
 105                                                 ms.WriteByte ((byte)0xBB);\r
 106                                                 ms.WriteByte ((byte)c);\r
 107                                         }\r
 108                                 } else {\r
 109                                         ms.WriteByte ((byte)0xEF);\r
 110                                 }\r
 111                                 break;\r
 112                         case '<':\r
 113                                 // try to get encoding name from XMLDecl.\r
 114                                 ms.WriteByte ((byte)'<');\r
 115                                 int size = stream.Read (buffer, 1, 4);\r
 116                                 ms.Write (buffer, 1, 4);\r
 117                                 if (Encoding.ASCII.GetString (buffer, 1, 4) == "?xml") {\r
 118                                         int loop = 0;\r
 119                                         c = SkipWhitespace (ms);\r
 120                                         // version\r
 121                                         if (c != 'v' || stream.ReadByte () != 'e')\r
 122                                                 throw new XmlException ("invalid xml declaration.");\r
 123                                         ms.WriteByte ((byte)'v');\r
 124                                         ms.WriteByte ((byte)'e');\r
 125                                         while (loop++ >= 0) {\r
 126                                                 c = stream.ReadByte ();\r
 127                                                 ms.WriteByte ((byte)c);\r
 128                                                 if (c == '0') {\r
 129                                                         ms.WriteByte ((byte)stream.ReadByte ());\r
 130                                                         break;\r
 131                                                 }\r
 132                                         }\r
 133                                         c = SkipWhitespace (ms);\r
 134                                         if (c == 'e') {\r
 135                                                 ms.WriteByte ((byte)'e');\r
 136                                                 size = stream.Read (buffer, 0, 7);\r
 137                                                 ms.Write (buffer, 0, 7);\r
 138                                                 if (Encoding.ASCII.GetString(buffer, 0, 7) == "ncoding") {\r
 139                                                         c = this.SkipWhitespace(ms);\r
 140                                                         if (c != '=')\r
 141                                                                 throw encodingException;\r
 142                                                         ms.WriteByte ((byte)'=');\r
 143                                                         c = this.SkipWhitespace (ms);\r
 144                                                         int quoteChar = c;\r
 145                                                         ms.WriteByte ((byte)c);\r
 146                                                         int start = (int)ms.Position;\r
 147                                                         while (loop++ >= 0) {\r
 148                                                                 c = stream.ReadByte ();\r
 149                                                                 if (c == quoteChar)\r
 150                                                                         break;\r
 151                                                                 else if (c < 0)\r
 152                                                                         throw encodingException;\r
 153                                                                 ms.WriteByte ((byte)c);\r
 154                                                         }\r
 155                                                         string encodingName = Encoding.UTF8.GetString (ms.GetBuffer (), start, (int)ms.Position - start);\r
 156                                                         if (!XmlConstructs.IsValidIANAEncoding (encodingName))\r
 157                                                                 throw encodingException;\r
 158                                                         ms.WriteByte ((byte)quoteChar);\r
 159                                                         enc = Encoding.GetEncoding (encodingName);\r
 160                                                 }\r
 161                                                 else\r
 162                                                         ms.Write (buffer, 0, size);\r
 163                                         }\r
 164                                         else\r
 165                                                 ms.WriteByte ((byte)c);\r
 166                                 }\r
 167                                 buffer = ms.ToArray ();\r
 168                                 bufLength = buffer.Length;\r
 169                                 bufPos = 0;\r
 170                                 break;\r
 171                         default:\r
 172                                 buffer [0] = (byte)c;\r
 173                                 bufLength = 1;\r
 174                                 enc = Encoding.UTF8;\r
 175                                 break;\r
 176                         }\r
 177                 }\r
 178 \r
 179                 // skips whitespace and returns misc char that was read from stream\r
 180                 private int SkipWhitespace (MemoryStream ms)    // ms may be null\r
 181                 {\r
 182                         int loop = 0;\r
 183                         int c;\r
 184                         while (loop++ >= 0) { // defends infinite loop (expecting overflow)\r
 185                                 c = stream.ReadByte ();\r
 186                                 switch (c) {\r
 187                                 case '\r': goto case ' ';\r
 188                                 case '\n': goto case ' ';\r
 189                                 case '\t': goto case ' ';\r
 190                                 case ' ':\r
 191                                         if (ms != null)\r
 192                                                 ms.WriteByte ((byte)c);\r
 193                                         continue;\r
 194                                 default:\r
 195                                         return c;\r
 196                                 }\r
 197                         }\r
 198                         throw new InvalidOperationException ();\r
 199                 }\r
 200 \r
 201                 public Encoding ActualEncoding {\r
 202                         get { return enc; }\r
 203                 }\r
 204 \r
 205                 #region Public Overrides\r
 206                 public override bool CanRead {\r
 207                         get { return stream.CanRead; }\r
 208                 }\r
 209 \r
 210                 public override bool CanSeek {\r
 211                         get { return false; } //stream.CanSeek; }\r
 212                 }\r
 213 \r
 214                 public override bool CanWrite {\r
 215                         get { return false; }\r
 216                 }\r
 217 \r
 218                 public override long Length {\r
 219                         get {\r
 220                                 return stream.Length;\r
 221                         }\r
 222                 }\r
 223 \r
 224                 public override long Position {\r
 225                         get {\r
 226                                 return stream.Position + bufLength;\r
 227                         }\r
 228                         set {\r
 229                                 if(value < bufLength)\r
 230                                         bufPos = (int)value;\r
 231                                 else\r
 232                                         stream.Position = value - bufLength;\r
 233                         }\r
 234                 }\r
 235 \r
 236                 public override void Flush()\r
 237                 {\r
 238                         stream.Flush ();\r
 239                 }\r
 240 \r
 241                 public override int Read (byte[] buffer, int offset, int count)\r
 242                 {\r
 243                         int ret;\r
 244                         if (count <= bufLength - bufPos)        {       // all from buffer\r
 245                                 Array.Copy (this.buffer, bufPos, buffer, offset, count);\r
 246                                 bufPos += count;\r
 247                                 ret = count;\r
 248                         } else {\r
 249                                 int bufRest = bufLength - bufPos;\r
 250                                 if (bufLength > bufPos) {\r
 251                                         Array.Copy (this.buffer, bufPos, buffer, offset, bufRest);\r
 252                                         bufPos += bufRest;\r
 253                                 }\r
 254                                 ret = bufRest +\r
 255                                         stream.Read (buffer, offset + bufRest, count - bufRest);\r
 256                         }\r
 257                         return ret;\r
 258                 }\r
 259 \r
 260                 public override int ReadByte ()\r
 261                 {\r
 262                         if (bufLength > bufPos) {\r
 263                                 return buffer [bufPos++];\r
 264                         }\r
 265                         return stream.ReadByte ();\r
 266                 }\r
 267 \r
 268                 public override long Seek (long offset, System.IO.SeekOrigin origin)\r
 269                 {\r
 270                         int bufRest = bufLength - bufPos;\r
 271                         if (origin == SeekOrigin.Current)\r
 272                                 if (offset < bufRest)\r
 273                                         return buffer [bufPos + offset];\r
 274                                 else\r
 275                                         return stream.Seek (offset - bufRest, origin);\r
 276                         else\r
 277                                 return stream.Seek (offset, origin);\r
 278                 }\r
 279 \r
 280                 public override void SetLength (long value)\r
 281                 {\r
 282                         stream.SetLength (value);\r
 283                 }\r
 284 \r
 285                 public override void Write (byte[] buffer, int offset, int count)\r
 286                 {\r
 287                         throw new NotSupportedException ();\r
 288                 }\r
 289                 #endregion\r
 290         }\r
 291 }\r